Mtb to commuter

I'm currently using my old dusty cheap mtb for a bit of commuting to and from work, I've done a bit of refurbishment, changed out the old knackered cassette and chain, new brake pads (discs) tightened up slackened cables and adjusted derailleurs accordinly. Nothing expensive just necessary stuff. Now it's running nicely it got me thinking on my way in to work this morning. I quite often run out of gearing and reach my top speed limited by the gears. I also have a suspension front fork which can't be locked. I wonder should / could I swap out the chain rings (and likely bottom bracket) to increase my gearing (guessing I'd have to put some/all the links I took out the chain back in) should I swap the front fork for something rigid or would I be better served just saving for a new bike? I like commuting on this bike as I'm not to precious over it and I am doing year round commuting in all weather's (cycled in this week but I am in Lancaster). Any advice greatly received.
0
Posts
Without some details though, as above.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools
Can you get a suitable cassette with an 11 tooth, if not then a 12 tooth, smallest sprocket?
I've a similar set up for commuting - a 15 year old mtb - with an 11-32 9 speed cassette matched with 42 or 44 tooth big ring which gives more than enough range of gears.